1. Field of the Disclosure
The present disclosure relates generally to near field communications.
2. Background
Near field communication, or NFC, is a set of short-range wireless technologies. NFC generally operates at 13.56 MHz and at rates ranging from about 106 kbit/s to 848 kbit/s. NFC always involves a reader (or initiator) and a tag (or target); the reader actively generates an RF field that can power a passive tag. This enables NFC tags to be configured so as to have very simple form factors such as tags, stickers, key fobs, or cards that do not require batteries. NFC peer-to-peer communication is of course possible, where both devices are powered. Devices that contain both reader and tag capabilities are called controllers.
Generally, NFC requires that NFC devices be present within a relatively close proximity to each other so that their corresponding magnetic fields can exchange information. Typically, a first NFC device transmits or generates a magnetic field modulated with information, such as the identity of the device into which they are incorporated. Thus a NFC device incorporated into a smartphone can contain information about the identity of the smartphone, among other things. This magnetic field inductively couples onto a second NFC device that is proximate to the first NFC device. The second NFC device may respond to the first NFC device by transmitting or generating its own modulated magnetic field and inductively coupling this magnetic field to the first NFC device.
Near field communications (NFC) devices can be integrated into a variety of portable or mobile devices, such as laptop or tablet computers, portable game devices, mobile phones, smartphones, etc., for example, to facilitate the use of these portable and mobile devices in conducting daily transactions.
The relatively small size of portable and mobile devices make them easy to lose or be stolen. A rider in a taxi can very easily put his/her mobile phone down on the seat beside them and then forget to take it when they get out of the taxi. A person sitting at a table in a café may walk away for a moment while leaving their mobile phone or tablet computer sitting on the table. A thief can quickly scoop up the phone or computer and walk off with it before anyone notices what has happened.